CN102998024B

CN102998024B - Novel temperature measuring method based on resistor-inductor (RL) circuit zero-input response

Info

Publication number: CN102998024B
Application number: CN201210483515.2A
Authority: CN
Inventors: 杨宁; 王博; 徐耀良; 朱海婷; 杨亚兰; 钟绍山
Original assignee: Shanghai University of Electric Power
Current assignee: Shanghai University of Electric Power; University of Shanghai for Science and Technology
Priority date: 2012-11-26
Filing date: 2012-11-26
Publication date: 2014-08-20
Anticipated expiration: 2032-11-26
Also published as: CN102998024A

Abstract

The invention relates to a novel temperature measuring method based on resistor-inductor (RL) circuit zero-input response. The novel temperature measuring method adopts a simple RL series circuit and controls zero-input response of the RL circuit through a singlechip, an inner comparator and a timer work cooperatively, so that the relationship between zero-input response time and resistance is built, and field temperature values can be obtained by replacing simple software algorithm with complex hardware circuits. The novel temperature measuring method replaces hardware units with software design by using a resistor, an inductor and the singlechip, improves economical efficiency of device application, and is strong in expandability, suitable for temperature measuring of thermistors, photoresistors, piezoresistors and gas-sensitive resistors, stable in performance and capable of being widely applied to parameter measuring of industrial fields. The novel temperature measuring method can replace traditional temperature-measuring sensors of thermistors and can be widely applied to temperature measuring of power plants, electrical fields and other industrial fileds.

Description

A kind of Novel temperature measuring method based on the zero input response of RL circuit

Technical field

The present invention relates to a kind of temp measuring system, particularly a kind of Novel temperature measuring method based on the zero input response of RL circuit.

Background technology

Temperature survey is a very important task in a lot of industrial control fields, needs dissimilar temp measuring method in Different field environment.Traditional temperature sensing means of widespread use at present has contact instrument, as: solid-liquid expansion type and pressure type temperature sensor, thermopair and thermal resistance thermometer, also have non-contact optical sensor, as: infrared measurement of temperature method and ccd image temp measuring method.

It is all simulating signal that traditional temp measuring method is exported as thermopair, thermal resistance and infrared temperature-test sensor, hardware circuit complexity, and system acquisition needs AD converting unit, and cost is higher; Novel thermometry ccd image analytical technology measuring principle more complicated, and the cost of CCD own is higher, image processing algorithm also comparatively bothers.

In order to optimize traditional Thermistor Temperature Measurement method, save hardware cost, zero input response characteristic based on RL circuit, by setting up the relation between the zero input response time △ t of resistance temperature t, resistance R, inductance L and inductive drop thereof, obtains corresponding temperature value.Application result shows, what the method can be effective, reliable, simple, economical carries out temperature survey, and has stronger extensibility, can replace traditional Thermistor Temperature Measurement sensor, can be widely used in on-the-spot thermometric.

Summary of the invention

The present invention be directed to traditional temperature measuring equipment circuit complexity based on bridge balance principle, the problem that required hardware resource is many, a kind of Novel temperature measuring method based on the zero input response of RL circuit has been proposed, adopt simple R L series circuit, by the zero input response of Single-chip Controlling RL circuit, internal comparator and timer collaborative work, thus zero input response time and sensitivity set up, and simple software algorithm replaces complicated hardware circuit to obtain scene temperature value.

Technical scheme of the present invention is: a kind of Novel temperature measuring method based on the zero input response of RL circuit, specifically comprises the steps:

1) set up RL test circuit: single-chip microcomputer the one IO port output connects ground connection after the inductance of series connection and accurate adjustable potentiometer, inductance and accurate adjustable potentiometer series connection central point connect comparer one input end, another input termination fixed voltage of comparer, comparer output connects single-chip microcomputer the 2nd IO port;

2) single-chip microcomputer the one IO port puts 1, and set to 0 and open timer in single-chip microcomputer simultaneously to an IO port after time t, single-chip microcomputer the 2nd IO port scanning detection comparator output, comparer output switching activity, timer cuts out and records flip-flop transition and be , according to frequency formula calculated rate, records current resistance R and frequency f numerical value;

3) change accurate adjustable potentiometer resistance, repeating step 2) obtain the corresponding relation of different resistance values R and frequency f;

4) constantly change accurate adjustable potentiometer resistance, repeating step 2) and 3) obtain the corresponding curve of resistance value and frequency, deposit internal memory in;

5) replace accurate adjustable potentiometer, repeating step 2 with resistance formula sensor) obtain the frequency values that current unknown resistance is corresponding, audit memory resistance value obtains current actual resistance with the corresponding curve of frequency, is the current resistance of resistance formula sensor.

Fixed voltage in described step 1) is from supply voltage dividing potential drop or select precision voltage regulator to obtain.

In described step 1), comparer can also can adopt independently integrated comparator to replace with the inner integration module of single-chip microcomputer.

In described step 1), inductance selects the insensitive copper-manganese inductance of temperature variation.

In described step 5), resistance formula sensor can be thermistor, photoresistance, voltage dependent resistor (VDR), gas sensing resistance.

Beneficial effect of the present invention is: the Novel temperature measuring method that the present invention is based on the zero input response of RL circuit, design concept is simple: based on a simple RL circuit, rely on its zero input response characteristic, utilize comparing unit, the counter unit of single-chip microcomputer, set up the relation between resistance R and zero input response time △ t and resistance temperature t thereof, reach the object of thermometric; Hardware spending is little: this sensor is only used a thermistor, an inductance, a single-chip microcomputer, replaces hardware cell with Software for Design, has improved the economy of application of installation; Extensibility is strong: this device is not only for thermistor temperature detecting, applicable equally for photoresistance, voltage dependent resistor (VDR), gas sensing resistance, and stable performance, can be widely used in the various parameter measurements of industry spot.The method can replace traditional thermal resistance temperature measurement sensor, is widely used in the temperature survey of power plant, the industry spot such as electric.

Brief description of the drawings

Fig. 1 the present invention is based on RL circuit zero input response circuit diagram in the Novel temperature measuring method of RL circuit zero input response;

Fig. 2 is the Novel temperature measuring method hardware schematic diagram that the present invention is based on the zero input response of RL circuit;

Fig. 3 is the Novel temperature measuring method Output simulation curve map that the present invention is based on the zero input response of RL circuit;

Fig. 4 the present invention is based on capture program process flow diagram in the Novel temperature measuring method of RL circuit zero input response;

Fig. 5 the present invention is based on resistance R curve map corresponding to frequency F in the Novel temperature measuring method of RL circuit zero input response.

Embodiment

Be illustrated in figure 1 simple RL series connection, wherein electric current shown in calculating formula (1), E is electrical source voltage, and R is circuit resistance.

, (1)

When t=0, S1 gets to 1 by 3, according to RL circuit zero input response principle, has:

，（2）

Separating this differential equation of first order obtains:

，（3）

，（4）

The wherein time .（5）

Based on this principle, power on the moment by single-chip microcomputer IO port controlling RL circuit, will introduce comparer and certain fixed voltage and compare, single-chip microcomputer is to the scanning of comparer output port level, time between counter records RL down circuitry and comparer output switching activity , hardware chart as shown in Figure 2.

According to formula (3,4,5) can simulation node Ur and 2 waveforms of Uo as shown in Figure 3: solid line represents comparer Uo output waveform.

Its high level time , (6)

in formula (5) the scale-up factor of proportional relation relevant with the comparative voltage of choosing.If , have , (7)

If ,

: .（8）

Its medium frequency and the scale-up factor k of resistance are the constants relevant with setting comparative voltage, inductance, and this constant can be demarcated and obtain by experiment.

Design calibration process, thermistor replaces with accurate adjustable potentiometer, and comparer other end comparative voltage is from supply voltage dividing potential drop or select precision voltage regulator to obtain.Comparer can also can adopt independently integrated comparator to replace with the inner integration module of single-chip microcomputer.Calibration phase constantly changes resistance value, records now timer count value storage.After gathering for several times, carry out nonlinear compensation storage according to record data.

Qualify Phase, is changed to unknown resistance resistance by precision resistor and carries out counter sampling, and count value is brought storage array into and calculated actual resistance.Capture program process flow diagram as shown in Figure 4.

Actual test resistance resistance R and sampling calculated rate f have following graph of a relation as Fig. 5: visible actual curve and principle analysis are consistent, there is good linear relationship, in application process, can realize the Measurement accuracy to scene temperature, and hardware cost is significantly less than the other kinds temperature sensor of identical rig-site utilization.This method is only used a resistance, 1 inductance (choosing is to the insensitive copper-manganese inductance of temperature variation), a single-chip microcomputer, replaces hardware cell with Software for Design, has improved the economy of application of installation; Extensibility is strong: the method is not only for thermistor temperature detecting, applicable equally for photoresistance, voltage dependent resistor (VDR), gas sensing resistance, and stable performance, can be widely used in the various parameter measurements of industry spot.The method can replace traditional thermal resistance temperature measurement sensor, is widely used in the temperature survey of power plant, the industry spot such as electric.

Claims

1. the Novel temperature measuring method based on the zero input response of RL circuit, is characterized in that, specifically comprises the steps:

1) set up RL test circuit: single-chip microcomputer the one IO port output connects ground connection after the inductance of series connection and accurate adjustable potentiometer, inductance and accurate adjustable potentiometer series connection central point connect comparer inverting input, comparer normal phase input end connects fixed voltage, comparer output connects single-chip microcomputer the 2nd IO port, and inductance selects the insensitive copper-manganese inductance of temperature variation;

3) change accurate adjustable potentiometer resistance, repeating step 2) obtain the corresponding relation of different resistance R and frequency f; By the accurate adjustable potentiometer resistance of continuous change, obtain the corresponding curve of resistance value and frequency, deposit internal memory in;

4) replace accurate adjustable potentiometer with resistance formula sensor, repeating step 2) obtain the frequency values that current unknown resistance is corresponding, audit memory resistance value obtains current actual resistance with the corresponding curve of frequency, be the current resistance of resistance formula sensor, resistance formula sensor is thermistor, determines corresponding temperature value by current resistance.

2. the Novel temperature measuring method based on the zero input response of RL circuit according to claim 1, is characterized in that, the fixed voltage in described step 1) is from supply voltage dividing potential drop or select precision voltage regulator to obtain.

3. the Novel temperature measuring method based on the zero input response of RL circuit according to claim 1, is characterized in that, in described step 1), comparer uses the inner integration module of single-chip microcomputer or adopts independently integrated comparator.